窄禁带半导体的自由载流子吸收

FREE CARRIER ABSORPTION IN NARROW-GAP SEMICONDUCTORS

从理论和实验上研究了77K和300K温度下,本征型半导体InSb,Hg_(1-x)Cd_xTe,Hg_(1-x)Mn_xTe和高掺杂Hg_(1-x)Cd_xTe在2.5～50μm波段范围内的自由载流子吸收,结果表明:对于所研究的三种本征型样品,均是极性光学声子散射起主要作用,对于InSb还应考虑声学声子和电离杂质散射。对有缺陷的Hg_(1-x)Mn_xTe样品,理论计算的自由载流子吸收系数与实验值不一致,表明存在附加的散射机制,对高掺杂Hg_(1-x)Cd_xTe的研究证实了这一假设。还讨论了非弹性电子-声子散射机制的起因,估算了特性参数。

Theoretical and experimental investigations of free carrier absorption (FCA) in intrinsic InSb, Hg_(1-x)Cd_xTe, Hg_(1-x)Mn_xTe and heavily doped Hg_(1-x)Cd_xTe in the wavelength range 2.5～50μm have been carried out at 77K and 300 K. It is shown that in all intrinsic compounds the scattering of polar optical phonons plays a dominant role. In InSb the soattering of acoustic phonons and ionized impurities is taken into account. The lack of satisfactory agreement between experimental and calculated FCA in less perfect Hg_(1-x)Mn_xTe points out the additional scattering mechanism. This assumption has been confirmed by investigations of FCA in heavily doped Hg_(1-x)Cd_xTe. The origin of inelastic electron-phonon seattering mechanism has been discussed and parameters estimated.